[BRLTTY] Monarch display and USB connection issues

[Jason J.G. White]

Dear BRLTTY users/developers,

I presently have access to a Monarch device on loan, which I know isn't 
supported by BRLTTY yet. (I would offer to help with testing if 
developers plan to work on BRLTTY support and if the owner of the 
Monarch agrees, but at this stage I can't establish a working USB 
connection - see below.)

It's a straight USB-C to USB-C cable supplied with the Monarch. If I 
attach the Monarch to my MacBook Pro via USB, the connection succeeds, 
as shown by the USB-related options that appear in the Connected Devices 
menu of the Monarch, enabling file transfer mode to be selected, for 
example. However, if I connect it to my older Lenovo ThinkPad P51 
machine with the same cable, the connection appears to fail under both 
Linux and Windows. This laptop has only one USB-C port. Connecting a 
different USB device to this port via a USB-C to USB-A adapter gives 
working data transfer, so it's possible that the port is indeed 
functioning properly.

The Monarch runs Android 13. I've raised this issue as a support request 
with APH, and it is being worked on, but I'm asking here in case anyone 
has additional clues about likely causes. (It might be my hardware - I 
acknowledge as much.)

The Linux kernel logs upon attempting a connection are as follows.

Sep 12 11:21:45 jpw kernel: xhci_hcd 0000:3d:00.0: new USB bus 
registered, assigned bus number 3
Sep 12 11:21:45 jpw kernel: xhci_hcd 0000:3d:00.0: new USB bus 
registered, assigned bus number 4
Sep 12 11:21:45 jpw kernel: xhci_hcd 0000:3d:00.0: Host supports USB 3.1 
Enhanced SuperSpeed
Sep 12 11:21:45 jpw kernel: usb usb3: New USB device found, 
idVendor=1d6b, idProduct=0002, bcdDevice= 6.16
Sep 12 11:21:45 jpw kernel: usb usb3: New USB device strings: Mfr=3, 
Product=2, SerialNumber=1
Sep 12 11:21:45 jpw kernel: usb usb3: Product: xHCI Host Controller
Sep 12 11:21:45 jpw kernel: usb usb3: Manufacturer: Linux 6.16.5-arch1-1 
xhci-hcd
Sep 12 11:21:45 jpw kernel: usb usb3: SerialNumber: 0000:3d:00.0
Sep 12 11:21:45 jpw kernel: hub 3-0:1.0: USB hub found
Sep 12 11:21:45 jpw kernel: usb usb4: New USB device found, 
idVendor=1d6b, idProduct=0003, bcdDevice= 6.16
Sep 12 11:21:45 jpw kernel: usb usb4: New USB device strings: Mfr=3, 
Product=2, SerialNumber=1
Sep 12 11:21:45 jpw kernel: usb usb4: Product: xHCI Host Controller
Sep 12 11:21:45 jpw kernel: usb usb4: Manufacturer: Linux 6.16.5-arch1-1 
xhci-hcd
Sep 12 11:21:45 jpw kernel: usb usb4: SerialNumber: 0000:3d:00.0
Sep 12 11:21:45 jpw kernel: hub 4-0:1.0: USB hub found
Sep 12 11:21:46 jpw kernel: usb usb3-port1: Cannot enable. Maybe the USB 
cable is bad?
Sep 12 11:21:47 jpw kernel: usb usb3-port1: Cannot enable. Maybe the USB 
cable is bad?
Sep 12 11:21:47 jpw kernel: usb usb3-port1: attempt power cycle
Sep 12 11:21:48 jpw kernel: usb usb3-port1: Cannot enable. Maybe the USB 
cable is bad?
Sep 12 11:21:49 jpw kernel: usb usb3-port1: Cannot enable. Maybe the USB 
cable is bad?
Sep 12 11:21:49 jpw kernel: usb usb3-port1: unable to enumerate USB device